Need help with QOS

Have just started reading about QOS and I understand it a bit but I am far from where I need to be. I'm curious if anyone can help me set up a QOS on my linksys WRT54G router. I play games that are sensitive to latency and use skype frequently. My roommates tend to stream/download while I am playing and I'd like to prioritize everything I am doing. I have set a static IP for myself and have been reading and searching for a couple of hours.. so any help is appreciated.

You're not going to the full 27mbps on that router with QoS enabled - the CPU will become a limiting factor. If you decide to implement QoS, you should try disabling the L7 filters and try to stick to port-based rules. Then enable it, test, and decide if the overall loss of throughput is worthwhile. An alternative if you just want to limit your roommates would be to use the bandwidth limiter rather than QoS.